This invention relates to a seal device for use in a rotary type regenerative heat exchanger which is used for a gas turbine.
Hitherto, it has been a common practice to urge seal members against the core surface of a heat exchanger by means of resilient members, which are supported by casing of a gas turbine engine, for the purpose of sealing the flat surface portion of the core against exhaust gases and air, the core having therein a plurality of independent, elongated holes having a small diameter. However, the aforesaid seal device poses difficulties in the assembly accuracy of resilient members as well as in controlling the accuracy in setting urging pressure for the resilient members. In addition, it is even more difficult to maintain a desired consistent seal-tightness, because of the variation in the pressure of the seal member being urged, which variation is responsible for the difference in the pressures of fluids prevailing inside and outside a seal member. For instance, if there occurs a reduction in the pressure of the seal members being urged against the flat surface portions of the heat-exchanger core, then the sealing function of the seal members will be impaired on the surface of the core, with the result that, in most cases, air at a high pressure leaks therefrom, thus reducing the amount of air being fed to a combustor of a gas turbine engine. This in turn lowers the output of an engine, with the accompanying reduction in fuel consumption rate. On the other hand, if there is created an excessively high pressure by the seal member being urged against the flat surface portions of the heat-exchanger core, then there results an extremely high frictional force acting on both members, thus leading to not only wear in the flat surface portions of the heat-exchanger core but also an increase in power for driving the heat-exchanger core. This then results in a lowering of the output of an engine, because the heat-exchanger core is driven by means of a turbine.